1. Technical Field
The present invention relates to tire pressure monitoring devices, and more particularly to a tire pressure monitoring device featuring for a valve stem that is inclinable with respect to a main body of the tire pressure monitoring.
2. Description of Related Art
Automobiles are undoubtedly the most important transportation means for the modern times. Therefore, the contemporaries put increasing attention to car safety. Among others, appropriate tire pressure is essential for safe and smooth driving. As compared with properly filled tires, low-pressure tires can consume more fuel during driving and make it more difficult for a driver to control the direction where a car proceeds, wherein the latter in particular endangers the driver and his/her passengers in car.
Recently, there have been many tire pressure monitoring devices on the market. For example, FIG. 1 is a conventional tire pressure monitoring device, which comprises a main body 1 and a valve stem 2 fixedly attached to the main body 1. The valve stem 2 is configured to be set in a valve-stem hole formed on a tire wheel rim 9 and work with a bolt 3 as well as a nut 4 to affix the main body 1 to the tire wheel rim 9, so that the main body 1 is allowed to monitor the tire pressure during driving all the time and warn the driver with a signal when the tire pressure is detected as abnormal.
It is noted that on various wheel rim products such valve-stem holes are locate differently. For easily adapting the valve stem 2 to different installation angles for most valve-stem holes, the washer and nut used to hold the valve stem 2 of the conventional tire pressure monitoring device about a valve-stem hole of a wheel rim 9 are typically round-headed, which allow the valve stem 2 to be inclined as needed. However, since the valve stem 2 comes integratedly with the main body 1, when the valve stem 2 inclines for adaptation, the main body 1 is likely to be lifted from the wheel rim 9 where it should rest on and become suspending about the wheel rim 9. Such a suspending main body 1 can be rocked under the centrifugal force generated by the rolling wheel, and this is harmful to the tire pressure monitoring device itself. Hence, in the course of attaching the tire pressure monitoring device to the wheel rim 9, it is important to ensure that the relative location among the main body 1, the valve stem 2 and the nut 4 is proper set. To this end, manual adjustment has to be carefully performed throughout the course of attachment, making the attachment inconvenience.